The present invention relates to an apparatus for producing casting mould parts by compacting sand or other like material between a vertical squeeze plate and a vertical swingable plate forming movable end walls in a squeeze chamber. The swingable plate can swing away after compaction to allow passage of the mould part from the squeeze chamber by further forward movement of the squeeze plate and the swingable plate is journalled on a front yoke which is in turn mounted on guide columns for movement relative to said squeeze chamber. A pull yoke is placed behind the squeeze chamber and connected to the guide columns. The front yoke, the pull yoke and the guide columns form a relatively rigid frame structure parallel with the longitudinal axis of the squeeze chamber. An apparatus of this kind is e.g. known from EP-231,741, and EP-020,082.
In such known apparatuses the pull yoke is only controlled in its movements by the guide columns and accordingly, uneven forces applied to the squeeze plate and the swingable plate, respectively, in connection with differently shaped patterns will cause a deformation of the relatively rigid frame structure consisting of the guide columns and the two connected yokes. In order to reduce such deformation and correspondingly reduce the tilting movement of the swingable plate, it is known, e.g. from EP-231,741, to provide bearings for the guide columns close to the front of the squeeze chamber and close to the back of the squeeze chamber. However, this will not completely prevent a certain tilting movement of the swingable plate during the compacting.
It is the object of the invention to further reduce such deformation and in accordance with the invention, this is achieved by the provision of means for guiding the pull yoke as discussed in detail hereinbelow. By means of this, the pull yoke is directly guided and supported against movements in a plane perpendicular to the intended movement of the frame structure and accordingly, a more rigid frame structure is achieved providing a more rigid guidance of the swingable plate, in particular preventing a tilting movement, without substantially increasing the dimensions of the apparatus, and without substantially increasing the weight of the moved frame structure consisting of the front yoke, the pull yoke and the guide columns.